Blog

2014.12.19

Typesafe Configを使って環境設定を切り替えしてみる

こんにちは。DynalystのHanです。Dynalystではアプリケーションの設定にTypesafe Configを使っています。

そこでProductionやテスト環境毎にアプリケーション設定をどう切り替えてるのかについて簡単に紹介したいと思います。

Typesafe Configを選んだ理由

Scalaをやる前まではJavaエンジニアだったのでアプリケーションの設定ファイルなら何も考えず.propertiesに定義するのは定番だけど、せっかくScalaをやり始めてるのでScalaの開発ではどのライブラリがよく使われているのかを調べていました。

そこで発見したのがTypesafe Configです。

.propertiesも勿論対応してますし、ResourceBundleより便利な機能がたくさんある。
そしてAkka, Play, Slick, SprayなどScalaでは有名なOpenSource Projectにもよく使われている。
HOCONが見やすい
あとはTypesafeという安定なネームバリュー！

Typesafe ConfigのソースコードはJavaで書かれています。

Typesafe Configの使い方

Typesafe Configの基本的な使い方やRuntime時の動き方は公式レポジトリのREADME.mdに詳しく書いてあります。

たとえば、以下のような設定ファイルがあった場合にConfigオブジエクトから値を取得することができます。

# file: application.conf

app {
  message = "hello world"
  numbers = [10, 20, 30]
}

# file: application.conf

app {

message = "hello world"

numbers = [10, 20, 30]

}

import com.typesafe.config._
val config = ConfigFactory.load()

val message = config.getString("app.message")
// message: String = hello world

val numbers = config.getIntList("app.numbers")
// numbers: java.util.List[Integer] = [10, 20, 30]

import com.typesafe.config._

val config = ConfigFactory.load()

val message = config.getString("app.message")

// message: String = hello world

val numbers = config.getIntList("app.numbers")

// numbers: java.util.List[Integer] = [10, 20, 30]

値はシステム環境変数から取得することもできます。たとえばSCALA_HOMEといったシステム環境変数があるとしたら

# file: application.conf
# export SCALA_HOME=/usr/local/Cellar/scala/2.11.4

app {
  scala.home = ${SCALA_HOME}

  message = "hello world"
  numbers = [10, 20, 30]
}

# file: application.conf

# export SCALA_HOME=/usr/local/Cellar/scala/2.11.4

app {

scala.home = ${SCALA_HOME}

message = "hello world"

numbers = [10, 20, 30]

}

val home = config.getString("app.scala.home")
// home: String = /usr/local/Cellar/scala/2.11.4

1 2	val home = config.getString("app.scala.home") // home: String = /usr/local/Cellar/scala/2.11.4

また、別ファイルに定義されている設定をincludeして使うこともできます。

# file: global.conf

global {
  message = "hello global.conf"
  numbers = [100, 200, 300]
}

# file: application.conf
include classpath("global.conf")

app {
  # scala.home = ${SCALA_HOME}

  message = "hello world"
  numbers = [10, 20, 30]

  global {
    message = ${global.message}
    numbers = ${global.numbers}
  }
}

# file: global.conf

global {

message = "hello global.conf"

numbers = [100, 200, 300]

}

# file: application.conf

include classpath("global.conf")

app {

# scala.home = ${SCALA_HOME}

message = "hello world"

numbers = [10, 20, 30]

global {

message = ${global.message}

numbers = ${global.numbers}

}

val message = config.getString("app.global.message")
// message: String = hello global.conf

val numbers = config.getIntList("app.global.numbers")
// numbers: java.util.List[Integer] = [100, 200, 300]

val message = config.getString("app.global.message")

// message: String = hello global.conf

val numbers = config.getIntList("app.global.numbers")

// numbers: java.util.List[Integer] = [100, 200, 300]

ここでincludeするときにclasspathというメッソドにinclude先のファイル名を渡していたのでこれを拡張もしくはあるinterfaceを実装すれば環境毎設定ファイルを読ませることができてそれぞれの値で置換できるんじゃないかと思い、ソースコードをみたところConfigIncluderというinterfaceと実装クラス発見！

ConfigIncluderClasspath.java – include classpath
ConfigIncluderFile.java – include file
ConfigIncluderURL.java – include url

Environment Protocolを定義して環境設定切り替え

urlからも設定ファイルがincludeできるのが分かったのでRuntimeの時にどの環境で実行されてるかを
認知できるcustom protocolを定義して以下のように書けることができます。

# env protocolはsystem propertyの`-Denv=${SYSTEM_ENV}`から{environment}を取得する
# {environment}は[production|staging|development]のどれかになる
# {environment}/env.confをincludeする

include url("environment:///<ENVIRONMENT>/env.conf")

# env protocolはsystem propertyの`-Denv=${SYSTEM_ENV}`から{environment}を取得する

# {environment}は[production|staging|development]のどれかになる

# {environment}/env.confをincludeする

include url("environment:///<ENVIRONMENT>/env.conf")

Environment Protocol定義

custom protocolを定義するには以下のinterfaceを実装してJVMがそのprotocolを認識できるように設定する必要があります。

import java.net.{URLStreamHandler, URLStreamHandlerFactory}

class EnvironmentURLStreamHandlerFactory extends URLStreamHandlerFactory {

  def createURLStreamHandler(protocol: String): URLStreamHandler = {
    protocol match {
      case p if p.startsWith("environment") => new EnvironmentURLStreamHandler
      case _ => null
    }
  }

}

import java.net.{URLStreamHandler, URLStreamHandlerFactory}

class EnvironmentURLStreamHandlerFactory extends URLStreamHandlerFactory {

def createURLStreamHandler(protocol: String): URLStreamHandler = {

protocol match {

case p if p.startsWith("environment") => new EnvironmentURLStreamHandler

case _ => null

}

import java.net.{URL, URLConnection, URLStreamHandler}

class EnvironmentURLStreamHandler extends URLStreamHandler {

  def openConnection(url: URL): URLConnection = {
    new EnvironmentConnection(url)
  }

}

import java.net.{URL, URLConnection, URLStreamHandler}

class EnvironmentURLStreamHandler extends URLStreamHandler {

def openConnection(url: URL): URLConnection = {

new EnvironmentConnection(url)

}

import java.io.InputStream
import java.net.{URL, URLConnection}

import com.typesafe.scalalogging.StrictLogging

class EnvironmentConnection(url: URL) extends URLConnection(url) with StrictLogging {

  def connect(): Unit = {}

  override def getInputStream: InputStream = mkInputStream(url)

  private def mkInputStream(url: URL): InputStream = {
    val path = url.getPath
    val env = resolveEnvironment
    logger.info(s"env(path: $path) - $env")
    getClass.getResourceAsStream(path.replace("<ENVIRONMENT>", env))
  }

  private def resolveEnvironment: String = {
    val property = Option(System.getProperty("environment"))
    val system = Option(System.getenv("SYSTEM_ENV"))
    (property, system) match {
      case (Some(env), _) => env // -Denvironment=[production|staging|development]
      case (_, Some(env)) => env // export SYSTEM_ENV=[production|staging|development]
      case _ => "development"    // default environment
    }
  }

}

import java.io.InputStream

import java.net.{URL, URLConnection}

import com.typesafe.scalalogging.StrictLogging

class EnvironmentConnection(url: URL) extends URLConnection(url) with StrictLogging {

def connect(): Unit = {}

override def getInputStream: InputStream = mkInputStream(url)

private def mkInputStream(url: URL): InputStream = {

val path = url.getPath

val env = resolveEnvironment

logger.info(s"env(path: $path) - $env")

getClass.getResourceAsStream(path.replace("<ENVIRONMENT>", env))

}

private def resolveEnvironment: String = {

val property = Option(System.getProperty("environment"))

val system = Option(System.getenv("SYSTEM_ENV"))

(property, system) match {

case (Some(env), _) => env // -Denvironment=[production|staging|development]

case (_, Some(env)) => env // export SYSTEM_ENV=[production|staging|development]

case _ => "development" // default environment

}

動作確認

# file: development/env.conf
env {
  message = "hello development environment!"
}

# file: staging/env.conf
env {
  message = "hello staging environment!"
}

# file: production/env.conf
env {
  message = "hello production environment!"
}

# file: application.conf
# export SCALA_HOME=/usr/local/Cellar/scala/2.11.4

include classpath("global.conf")
include url("environment:///<ENVIRONMENT>/env.conf")

app {
  # scala.home = ${SCALA_HOME}

  message = "hello world"
  numbers = [10, 20, 30]

  global {
    message = ${global.message}
    numbers = ${global.numbers}
  }

  env {
    message = ${env.message}
  }
}

# file: development/env.conf

env {

message = "hello development environment!"

}

# file: staging/env.conf

env {

message = "hello staging environment!"

}

# file: production/env.conf

env {

message = "hello production environment!"

}

# file: application.conf

# export SCALA_HOME=/usr/local/Cellar/scala/2.11.4

include classpath("global.conf")

include url("environment:///<ENVIRONMENT>/env.conf")

app {

# scala.home = ${SCALA_HOME}

message = "hello world"

numbers = [10, 20, 30]

global {

message = ${global.message}

numbers = ${global.numbers}

}

env {

message = ${env.message}

}

import java.net.URL

import com.typesafe.config.ConfigFactory
import com.typesafe.scalalogging.StrictLogging

object EnvironmentConfigMain extends StrictLogging {

  /**
   * {{
   * sbt run
   * sbt 'run development'
   * sbt 'run staging'
   * sbt 'run production'
   * }}
   * @param args environment value[development|staging|production]
   */
  def main(args: Array[String]): Unit = {
    URL.setURLStreamHandlerFactory(new EnvironmentURLStreamHandlerFactory)
    System.setProperty("environment", args.headOption.getOrElse("development"))
    val config = ConfigFactory.load()
    logger.info(config.getString("app.env.message"))
  }

}

import java.net.URL

import com.typesafe.config.ConfigFactory

import com.typesafe.scalalogging.StrictLogging

object EnvironmentConfigMain extends StrictLogging {

/**

* {{

* sbt run

* sbt 'run development'

* sbt 'run staging'

* sbt 'run production'

* }}

* @param args environment value[development|staging|production]

def main(args: Array[String]): Unit = {

URL.setURLStreamHandlerFactory(new EnvironmentURLStreamHandlerFactory)

System.setProperty("environment", args.headOption.getOrElse("development"))

val config = ConfigFactory.load()

logger.info(config.getString("app.env.message"))

}

これでそれぞれ環境を引数でsbt runすると

[typesafe-config-example (master=)]$ sbt run
...
[info] Running EnvironmentConfigMain
14/12/18 13:42:35.848 INFO  EnvironmentConnection - env(path: /<ENVIRONMENT>/env.conf) - development
14/12/18 13:42:35.858 INFO  EnvironmentConfigMain$ - hello development environment!
[success] Total time: 1 s, completed Dec 18, 2014 1:42:35 PM

[typesafe-config-example (master=)]$ sbt run

...

[info] Running EnvironmentConfigMain

14/12/18 13:42:35.848 INFO EnvironmentConnection - env(path: /<ENVIRONMENT>/env.conf) - development

14/12/18 13:42:35.858 INFO EnvironmentConfigMain$ - hello development environment!

[success] Total time: 1 s, completed Dec 18, 2014 1:42:35 PM

[typesafe-config-example (master=)]$ sbt 'run development'
...
[info] Running EnvironmentConfigMain development
14/12/18 13:47:24.934 INFO  EnvironmentConnection - env(path: /<ENVIRONMENT>/env.conf) - development
14/12/18 13:47:24.943 INFO  EnvironmentConfigMain$ - hello development environment!
[success] Total time: 3 s, completed Dec 18, 2014 1:47:24 PM

[typesafe-config-example (master=)]$ sbt 'run development'

...

[info] Running EnvironmentConfigMain development

14/12/18 13:47:24.934 INFO EnvironmentConnection - env(path: /<ENVIRONMENT>/env.conf) - development

14/12/18 13:47:24.943 INFO EnvironmentConfigMain$ - hello development environment!

[success] Total time: 3 s, completed Dec 18, 2014 1:47:24 PM

[typesafe-config-example (master=)]$ sbt 'run staging'
...
[info] Running EnvironmentConfigMain staging
14/12/18 13:47:33.243 INFO  EnvironmentConnection - env(path: /<ENVIRONMENT>/env.conf) - staging
14/12/18 13:47:33.253 INFO  EnvironmentConfigMain$ - hello staging environment!
[success] Total time: 1 s, completed Dec 18, 2014 1:47:33 PM

[typesafe-config-example (master=)]$ sbt 'run staging'

...

[info] Running EnvironmentConfigMain staging

14/12/18 13:47:33.243 INFO EnvironmentConnection - env(path: /<ENVIRONMENT>/env.conf) - staging

14/12/18 13:47:33.253 INFO EnvironmentConfigMain$ - hello staging environment!

[success] Total time: 1 s, completed Dec 18, 2014 1:47:33 PM

[typesafe-config-example (master=)]$ sbt 'run production'
...
[info] Running EnvironmentConfigMain production
14/12/18 13:47:41.401 INFO  EnvironmentConnection - env(path: /<ENVIRONMENT>/env.conf) - production
14/12/18 13:47:41.414 INFO  EnvironmentConfigMain$ - hello production environment!
[success] Total time: 1 s, completed Dec 18, 2014 1:47:41 PM

[typesafe-config-example (master=)]$ sbt 'run production'

...

[info] Running EnvironmentConfigMain production

14/12/18 13:47:41.401 INFO EnvironmentConnection - env(path: /<ENVIRONMENT>/env.conf) - production

14/12/18 13:47:41.414 INFO EnvironmentConfigMain$ - hello production environment!

[success] Total time: 1 s, completed Dec 18, 2014 1:47:41 PM

環境毎に値を取得することができました！

まとめ

アプリケーション設定をしていた時にapplication.confの中身が${database.url}なっていてあまり直感的なじゃないというのとテストのためにもCustom Protocolを設定しないといけないのはデメリットかもしれません。

Dynalystではテストにspecs2を使っていてテスト環境用の値が取得されるようにtrait EnvResolvedSpecificationをよいしています。

またサーバーやバッチにはtrait EnvironmentProtocolResolverをよいしてmainクラスにmix-inして使ってます。

本文で使っていた例はGithubに公開されているので違うやりかたで環境設定を解決している方は是非教えてください！

Author

sangwon